Air brake



C. A. CAMPBELL spt. is, 1933.

AIR BRAKE 8 Sheets-Sheet 1 Filed Feb. 21, 1951 www Clttorncgs Sept. 26,1933.

c. A. CAMPBELL 1,928,091

AIR BRAKE Filed Feb. 21, 1951 8 Sheets-Sheet 2 Suvcntor 59 55 3 @www en.@www Gttorncgs Sept 26 1933- c. A.,cAMPBl-:LL 1,928,091

AIR BRAKE Filed Feb. 21, 1931v 8 sheets-sheet 5 EJTEICTED 399 ELEAJLAND90 Richman QUICK JEVICE,

399 EMEEGEN CY 92 lhwcntor ema/awww@ M Lttorncus Sept 26 1933- c. A.CAMPBELL AIR BRAKE Filed Feb. 21, 1931 8 Sheets-Sheet 4 Snucntor @Lawa/.

545 m W 1w Gttornegs SeP- 26, 1933 c. A. CAMPBELL 1,928,091

AIR BRAKE Filed Feb. 21, 1931 8 Sheets-Sheet 5 lill lmcntor @Mdm/HAMMSePt- 26, 1-933 c. A. CAMPBELL AIR BRAKE Filed Feb. 21, 1931 8Sheets-Sheet 6 3 mentor @glade/MCL @ann/lobe@ u. @N l. N n f :Si a W/ EnE v \\i. E

Gttornegs sept. 26, 1933. c. A. CAMPBELL 1,928,091

AIR BRAKE Filed Feb. 21, 1931 8 Sheets-Sheet 7 FH... 95 Snrcntor '92.911y299 20@4 eemmcmpb Sept. 26, 1933. c. A. CAMPBELL 1,928,091

AIR BRAKE Filed Feb. 2l, 1931 '8 Sheets-Sheet 8 3 nvcntor ew@ @wwwGttorncgs Patented Sept. 26, 1933 BRAKE lCharles .'AwGampbell,Watertown, N. Y., 4assignor toThe New .Kork `Air Brake Company,` acorporation of,New 'Jersey The 'prime object of-the presentinvention isto Vretain the advantageous operative `characteris` `tics of theWellknovJn-'typ'e K'triple Valves (such as local quick servicevvventing,` retarded release, `restricted recharge) andadd "to v"them -anumber lof advantageous lchiaractxaristics'and functions.

vThese added-characteristics andfunctions are,v

generally stated, reduction to therninimum rof the `risk lof an'undesiredveniergencyapplication, 'ability to Vinitiate-an emergencyfunction after of V"brake cylinder pressure in' emergency applications,quicker and ',rnore vuniform Yrelease -thi'oughout Aa trainydissipationoovercharge (if any) in auxiliaryjreservoirs afterV restricted reto slowkbrake pipe reductions. f v- Individually consideredjsome ofthe'functions and `characteristics above Veninnera'ted 'have beenproposed'hefore, but never, so far `as applicant is advised, has-therebeen-evolved a sirnple kand practicable Inode of combining them iniasingle "structure Car interchange introducestheVre- `quirernent that anynew triple valveto'be considered l for commercial radoption, v4must`operate satisfactorily in trains of lmixed equipment r(old and new)vmixedequipment train" is superior tothe operaticn'of aso'lid train ofoldequipment.

Another advantage `of marked importance is the fact that -eicistin`gstandard equipmentca-n be Achanged overVA tlor'riloody the presentinvention, so that confiplete"and` rapid-'conversionvto the "presentvalve 'as standardiis:economicallyfpossible. `"(erierallystatedychangeover 'from the 'present standards-using the Ktype triple Valve 'involves'instalia'tiongf abrake pipe vent valve, `and ian l M v U.':restrictedmeleasefand'zrechargecposition. y N

f .'"Fig, f6- isia esimilarviewfsshowinginthe partsiin ivadditionalv v(supplemental) reservoir.v "the triplevalve structnrenew `parts. areAsubstituted Aany'servicereduction,-cielayed'orthreeestage riserangement is shown. fSuch diagrammatic Yarchargeyand increasedsensitiveness in response 'The present valve not only lmeets thatrequirement-lentille operation o'i thel entire' bushingslide-valv;retard spring; alsof-the en f taining'tlie reservoir 4feedch'eck valve,and the pistons and valvesforV controlli-ng the ener'gencybrake-cylinderf` l{pressi-1re' rise' characteristics; The retard `stopis modiedg Y'The 4front cap is slightlylmodied .and a secondgraduatinglspring `is added.'. The auxiliary reservoir, brakecylinder,

centrifugal" dirtl -collectorf-cut-out #'cock, rbleediftheliK'tripleatothe*auxiliary reservoir.`V f Y, 1

".Ihe desir-ability of using .as `many aparts-of eX- isting triplevalves asljpossibla 4affects :considen for illustration, but it lWillloe"understoodvtnat '6,5 cock andl retainer remainvunchanged. Longerstuds are substituted ffor Athe-studs which ait-tach ,79 Lerable degreethedesign oflithee'mbodfiment-.chosso far as the operative features'ofthe valve are I concerned, -manychanges in -formand-arrange- 4V,Ir-lent, may jbe-lfound-desirable. j

Yinstallation In -Athe drawings aty-pe =-K..va'lv'e changed over ytoembody' thel invention V-is illusftrated. Alancer-tain of the'guresltheactual structure is shown, while in others a diagrammatic a/r'-rangement is functionally identicalgwith the actual construction; =loutvhas-ftheadvantage, for de-4 scriptive purposes, *thatlallfthevportsarebrought int'o a single -plane"softhat ina-"single viewitis v lpossible toftr-ace' all the-'flowsAv Vjl-ifich-*taire-place.

In the drawings,`- Y l ,A 'Fi'g-- i1 is,-an' elevationshowingtheequipment forone car. 1Portions only o f the brake pipe,

"reservoirs, and brake' vcylinder-p'ipe, Aare shown,

and the brake cylinder `is omitted altogether.

VA"ll'ieseparte however,V confor-xn'lto \=known pracv tice, are-notinvolved thelinvention; andrsvvill' vary insome degree according tolfthe '1 type of 'and shows the'V constructionl inf `fthe., vemergencyventfvalveandthe .manner gof connecting vttfo thefbrakeiiipe. p

Fig. the ,vtriplegfslide v,valve -fwith its-seat ,and gradurelease andrecharge position. V- .I

Eiggviissza, similar .'viiewashovving 4theapartjs in quickisenviceaposition.

full service position.

' seat. m

Fig. 14 is a Fig. 8 is a similar view showing the parts in emergencyposition. This is the same position as isassumed in what is knownas'ove'r-reduction position,'that is, the position assumed when brakepipe pressure is reduced12 pounds or `more below the point oiequalization withauxiliary reservoir pressure.

Fig. 9 is a diagrammatic view on an enlarged` scale, showing theactuating piston and valve which control the delayed build-up ofbrakecylinder pressure, the parts being illustrated at the terminationof their iirst or partiall downward movement.

Fig. 1G is asimilar' View showing the .position z assumed by the partsafter the piston has moved to 'its lowermost limit of motion. -V

Fig.` 11 is a similar view of the'y parts, showing the position assumedafter the pistonv has started -to move .up and khas carried thegraduating valve far enough to lap-the lower port in the shifting Fig.12 is a Vertical axial section throughthe triple valveas actuallyconstructed.

Fig. 13 is an elevation. of the filler block or adapter orconnecting thesupplemental reser- Voir.Y In this view the adapterl is shown as itwould appear Ylooking to the right relatively to Fig.12 l section'on theline 14-14of Fig. 12. Fig. 15 is `an elevation ofthe triple valve, asactually constructed, connected with the auxiliary and supplementalreservoirs. l

Fig. 16 is a plan View ofthe seat for the ltriple slide Valve, showingthe actual. location of the ports. :.v

Fig. 17 is a plan View of the triple slide valve, showing the actuallocation o1 ports in the top face, and showing, in dotted lines, therconnecting passages through the body of the valve.

Fig. -18 isa side elevation of the triple slide valve.

Fig. 19 is a view of the lower vface of the triple vslide valve, showingthe actual location of the ports, and in dotted lines the connectingpassages Ythrough the body or the'valve.

Fig. 20 is a section on the line 2 0'- 20 of Fig; 19. Fig. 21 is aviewofthe lower face of the graduating Valve used with the triple slidevalve, showing the actual location of the quick service cavity. f

Fig. 221s an end elevation of the triple slide vvalve.- 1

Fig..23 is a fragmentary View, similar to a por-` tion of Fig. 14,-andshowing a modification in Whicha single specially formed spring issubstitutedfor the double spring mechanism shown-in Fig. 14.

Figi 24 is a similarview showing the substitu Y tion of a single simplecoil spring for the double spring shown in Fig. 14. This substitutionproduces .the mechanism disclosed in my' .prior application Serial No.v439,743 above'identified.

- Fig; 25 is asimilar view showing a` further modicationvin whichYanother special form of spring is used.

Fig. V26 is a'fragmentary view, showing a modie'ation in which acharging groove in the piston bushing is used. Y

The passages in the slide valve are formed Vby the familiar practice ofdrilling and plugging.

vNderfortto"il1ustrate'fthis in Figs. 17a to 2l has been made, as it isacommon -practice,*and Wouldconfuse the drawings.

The brake pipe and connections brake pipe appears at 31. matic airbrakes, the brake pipe extends throughout the length of the train, isconnected from car to car with the usual brake-.pipe hose and cou-Vplings, and is equipped with theusualangle cock at each end of each car.These details are not illustrated. Pressure in the brake pipe is con-Vtrolled as usual by the engineers brakev valve, which may, so far as thepresent invention is con- VYcerned, be of any suitable type.

There is introduced in the brake pipe, near the y middle of the car, aspecial branch pipe T or connection 32 which is provided with a boltingange 33, intended to be connected to the framing ofv the car.theportions of the brake pipe 31 on opposite sides or the connection 32are alined with each other. The path of ilow between the two sectionsofthe brakepipe isd'ened vby a troughlike member 34, which is open at itstop to the Construction of emergency vent 'vuelves4 The connection `32isformed at one side with l A' a'bolting face kor pad having an openingleading 110 to the chamberV 35 and adapted to receive the bolting ange 36`for the bodyr37 Aof the emergency vent valve. Connecting bolts areindicated at The flange 36 isrecessed to receive a gasket 39 andstrainer 41 whose forms are clearly shown in the drawings. l Y

The top vof the body 37 is closed by a removable cap 42 held inY placeby machinev `screws and sealed by a gasket, as clearly indicated in they43 is bolted in place and is counterbored to sus'.

tain a cylinder bushing 44 which is' provided at its lower margin withanupstanding rim45, and

`which carries the suspending armsA 46.-v The The connection 32 is socontrived that 1' -plication Serial No. 560,806, 1 iled September 2, 05

arms 46 carry a central hub 47 upon which isv .threaded a cup-like guide48. This guides a piston stop 49 which is urged upward by a coil spring51. The member 43 is held to the body 37 by means of T- headed'bolts,asjindicatedand a gasket`52 seals the tWo parts together andialsoprovides' a sealed joint with the bushing44.

. Working in the bushing 44 is a piston 53. This is formed withadownwardly projecting pilot or stem 54 whichv works in--a-guidewayformed in the hub 47 and isin thrust'relation with the piston stop 49.The stem..54 hals anvaxialport 55 extending from Vthe upper face Yof thepiston and communicating witha lateralport 56` which dis'-V charges intoan annular groove 57.

The piston carries on its lower'face a gasket) 58 which fin thelowermostposition ofthe piston, seals against the rim 45. The parts 'areA sodimensioned that in the uppermost positionfof the piston stop 49 thegasket 58 `is held slightly above the rim 45, While the groove 57 isslightly, below the upper margin of the hub 47. The *itY of the stem 54in the hub 47 issuch as to rrestrict the 'reo 'above the 'piston 53,forcing-this piston down- Ward. 'Under ordina'ry circumstances, thepistonv new *of air fr'on the space above th'episton 5 3 tio the chamber43, to a desired charging rate. The purpose of lthe gasket 53 and spring51 is to init sealing of the pistn on its gasket during heavy charging'ow, and the freeing of the gasket from the rim 45 when charging iiowceases, to the end that Athe charging rate is controlled by the `rit ofthe lstem '54 in its guide, and the gasket may never freeze tov the rim45.

Ihe piston 53 carries three upstanding pins 59, two bf whichare visiblein Fig; 2. These'pins projectupwardly into the space within the body 37way of three passages formed in the lower wall ofthe' body'37'. Ampleclearance is'afordedaround thepins 59 `Ior the free flow of air from thespace within the body 37 to the space immediately above the piston y53.Each pin 59 is provided with two "spaced shoulders@ and 461, and thereduced upper 'portions of the pins'each pass through lugs Afern'ied ontwo fsuperposed valve members '-62 ancie- The lower valve v62 carries arubber gasket, 'clearly shown in the drawings, which seals against anannular valve seat 64 carried by an upstandi'ng boss within the body 37.This gasket is retained-by a tubular member 70 which is threaded into4"and extends through the valve 62, thus providing a port through thevalve. The upper valve 6 3 has :a rubber-gasketed face lwhich sealsagainst 'the valve seat 65 formed on the upper end or member 70. The twovalves are urged in a closing direction by a coil spring 66 which isconned at its lower end in a cup 67 on the upper face of the of thepiston 53 will unseat the valve 63, whose feffective area, andconsequent resistance to open'- infgjis relatively small. Opening of thevalve 63 l`'relieves the' pressure on the upper side of piston ,53 and,also on the upper side of the valve 62.

Hence vthe upward tendency of piston 53 is sharply increased, theresistance of the valve 62 to open- ,ing is reduced, and'extremely rapidaction is secured.

'I he A,valves 62 and 63 control the flow to vent ports l69. These .leadin opposite directionsto atmosphere, and one is visible in Fig. 2.Theother `issimilarand forward of the plane of section.

Thebrake pipe vent valve Ajust described will be recognized as belongingto a general species known in, the air brake art. The detailsl of thepiston and 'valve constructionare novel, but are not claimed herein, asthey form the subject mat- 'ter'cf application Serial No.`563,6l9, ledSeptember 18, 1931, as a -continuation of application While I prefer thevent 1 `valve illustrated, ,because .of its very large capacity andrapid action,v other approximate equivalentsr might be substituted.

Operation f brake 'pipe vent valve The'operatio'n o f the valve is'asfollows: 'Wlienbrake pipe pressure rise s as it does, for fexarriple,during releaseiof ithe brakes','air flows 4from the brake pipethroughthe chamber 3 5 into the chamber within th'e'bod'y 37`an`d'to`the space53 will move 'downfar enough to seat the gasket 58 on the rim 45 and thespace Within the rcharnber-43 will be charged at a rate controlled bythe valve 631, at rwhich time thev chamber`` 43} wil1 be,

ventedfby flow back to the brake' pipe, flow taking place'throghthe port56 and passagej55.'

In the case of a rapid drop in brake pipe pressure, such :as-occurs inemergency'applicatio'n, the

possible'back 'flow is inadequate to reduce 'the pressure in chamber 43as fast as brake pipe pres# sure is reduced. 'The resultingvdiierential'pres-v sure forces the piston 53 to itsuppermost-,pesiv-tion,".open ing the valves 63 and'a62, and locallyventing thevbrake pipe, celerates Athe pressure drop inthe brake-pipe,In thisway van emergencydrop in brake pipe pressure initiated .by theengineerfs'vbrakevalveisY propagated and accelerated in its travelthroughout the length of the train atan extremely rapid rate. n Y' It ischaracteristic lo'f the present'invention that the propagation of theemergency pressure drop is controlled solely by the emergency vent valveand is wholly independent o'f the triple valves,v liloreov'er, thevfunction of thef "vent valves is controlled solely by the rate o-brakepipe pressure drop, not by thedegreeqof suchL drop.` Consequently, anundesired .emergency Vcan not be initiated by a sticking triple valve ascommonly happens where the emergency 'func- I This local venting ac tionis performed by apart of thetriple valve f rnechariism.-i Furthermoreitis vpossible to initiate an remergency pressure drop, and accelerate itthrough the operation of thevent valves, even after a substantial`service reduction. of brake pipe `pressure has been made. Thesecharacteristics result inr greatly improved operation `of the brakesystemas-a whole.

f Connections totrz'ple valve The branch pipe 7l leads to the triplevalve from the lower 4side of the lconnection 32, as

shown, and is equipped with. the usual cut-out" cock 72 andcentrifugaldust collector 73. The branch pipe is connected to thetriple valve by fmeans of the usual Vunion 74 equipped Withthe usual strainer thimble 75,see Figsfl ande,y Construction of trz'piepalve rIhe triple valve isshowndiagrainmatically in Figs. 3 to 11,'a'nd as actuallyconstructedinFigs.l2 to 22. In most instances the diagrammatic arrangement involvesshifting of certain component mechanisms, to bring therriinto acorn-V inon plane of isectior 1 ,'the location-fof 'allgports fin' the=plane o f',section',f`a'nd similar changes which Yci@y not;Y affect the rampen-"fthe device.

An incidentalY result is a'change inthe- 'fform and dimension. ofcertain passages,r whichchanges A'are without functional sigriicancefitbeingclearly understood thatA the vdirigrarnlnzntic-iigL f ures `donotvshow the' correct proportion-ing ,pf v`all ports. 'Ihe'porting'off the`slide valveand its seat, oncasual inspectiomwill appearIto,departf`infthe diagram quite radically from the porting Ain fthe jvalveas:actually constructed,V for the freason that in uieactuaiconerrueueneenairrlexpes so vit of the stem 54 in the hub 47.-Thischarging v l rate is made slow enough to insure thatthe cham"dients have been adopted to simplify manufacf ture and reduce the sizeofthe parts.

rThe device will rst be explained on the basis of the diagrammaticshowing, with only occasional reference tothe structure shown in Figs.12 to 22. Y After the operation has been traced,

' the porting of the slide valveA and its seat as actually embodied willbe explained.

- The union 7.4 connects the brake pipe directly tothe lower .bodyportion 76 of the triple valve. This is of specialform tosupport andhouse the build-updelay mechanism hereinafter described. Theremainingbody structure of the triple valve consists of the main bodyportion 77, which from gaskets.

Figs. 12 and 14 will be recognized as identical with that used for astandard type K triple (except for additional porting), the delaycylinder insert 78 and the front cap 79,V which last is speciallymodified to guide and support a double spring 20 graduating, st em.

The front cap gasket 81 is similar in form and identical in functionvwith the present standard The cylinder bushing 82 departs from presentstandards in the omission of the charging; groove. Thetriple piston 88and the graduating button 84 are unchanged from thecorresponding partsof the type K triple valve. The retard stop 85, retard stop spring 86,the guide cap 87 for the retard stop and its bushing 88,

are functionally similar to corresponding parts of ther; triple, butembody a new .construction devsigned to permit the use of a heavierretard stop spring and to provide a longerjguiding surface for theretard stop. This is rendered advisable by the use of the heavierspring.

The parts numbered to 88 are not herein claimed speciiically, but formthe subject matter of my application for patent, Serial No.

Figs. 3 and 12, and is held to its seat by the usual bow-spring 95. Thegraduating valve 92 is seated byra leaf spring 90. The auxiliaryreservoir 97 ris unchanged, but instead of mounting the body 77 directlyon the head of thereservoir, a'ported annular iillerpiece'98 isinterposed, gaskets 99 being used on .bothY faces to secure tight`joints with thereservoir and with the body of the triple valverespectively. The ller piece `98 affords connection for the pipe Y101which leads vto the vsupplemental reservoir 102 (See Figs.` 1 and 15).

The reservoir 102 isof ordinary form and its volume slightly exceedsthat of Y the auxiliary reservoir 97.V 1n actualpractic'e use has beenmade of an auxiliary reservoir, whose capacity is 2440 cubicinchesasupplemental reservoir whose capacity is 8088 cubic inches.

" The brake cylinder pipe v103 leads through the auxiliary `reservoir 97to the brake cylinder (not shown) as is .standard practice in freightbrakes. The pipe 103 registers with a passage'in the iiller .piece 9 8which forms acontinuation of the brake i cylinder passage 104 in body77.

As stated, the front cap 79 ismodiied to carry` a special graduatingvstein 105 which isguided in the guideway in the plug 106.l The plug 106is screwed into and seals `an opening formed in the front cap to receiveit. The stem 105 carries acollar 107 which li-mits the forward motion ofthe stem'by collision with seat 10,8 inthe front cap, and also serves asa seat for a light. graduating spring 109. When the 4stem 105 is forcedback a slight distanca'thecollar 107 engages a ange 111 on ring 112which is normally'held against the seat 108 by a secondand relativelystiff graduating spring 113. j Y

The actionof the graduating stem and retard stop can now be described: Y

Inv normal release position (Figs. 3, 4 and 12) the end of stem 98engages retard stop 85 .without compressing spring 86. In restrictedrelease position (Fig-5) the stem 93 forces stop 85 inward against theresistance of spring 86 until rim 221 on the piston 83 seats against theend of bushing 89. At such time the groove 219 affords communication tothe annular area outside rim 221.

In `quick service position (Fig. 6) stem 93 is arrested when button 84engages stem105, without compressing spring 109. Full service position(Fig. 7) is assumed when stem 105 is forced back compressing spring 109until collar 107 engages ange 111 without compressingspring 113.

ico

In emergency andv over reduction positions (Fig. 8) bothjsprings 109 and113 are overpowered, and piston 83 seats against gasket 8l.

The proper positioning of the slide Valves involves proper correlationof the positions of seat 108 in the front cap, flange 111, the amount oflost motion between stern 93 and valve 91, .and

the locations of the ports.

The insert member 78 is mounted in a recess, the upper'portion of whichis the space formerly occupiedin the K triple valve by the emergencypiston and emergency valve, and the lower portion of which is formed inthe lower body portion 76. insert 78 is formed with a flange 114 whichseats ona shoulder formed in the member 76 to support it. When sosupported the upper face of the ange is flush with the upper face of themember- 76 which mates with fthe body 77. The lower end of the'rnember78 is sealed against the bottom of the recessin the member 76 by aported gasket 115. A second gasjket 116 seats onY the upper face of thevmember 76 and on the upper face of the flangeA 114 andseals the jointwith thebody 77. The details of construction of this insert and itsrelation to the parts of the body, form the subject matter of anotherapplication, Serial No. 550,805, vfiled Sept. 2, 1931 and are not herespecifically claimed.

The upper end of the insert 78 seals in the'body 77 by means of a ringgasket 117. The upper end of the insert 78 is reduced indiameter toafford an annular passage 118 around the insert 78 which communicatesdirectly'with the brake 'cyl'- inder passage 104. This, as alreadyexplained, is in direct comrminicationV with brake cylinder pipe 103.The gaskets. 116, 117, isolate the passage 118 from the space 119withinthe insert 78.' The space 119 communicates directly with serviceand emergency ports in the seat for slide valve 91, asV 'i permit thesubstitution of plugs having ychoke ports of different sizes. This chokeport con- .trols the'rate ofbrake cylinder pressure built up in thesecond stage of em e rg'ency, and the purpose `of'changing thesize ofthe choke `isto permit ,controlof the' rate ofbuld-up.` f f vce pressedinte the upper end ofthe msere'zs is ably mounted a sluiting 'seat '123]The upper end of the bushing 1221s opfento the space119l Be-vv low thebushing l12'2 the iinsert is ormedwith'a slightly larger'fcliamberinWhich'is pressed af cylinder, bushing 12,4 which serves' asa c 'y'linder1 for the piston -125vr 'I his piston is providedd with anordirary`-'snapring 126', Tightffsealing of the piston is not, ho'w'ever;lessential, andthe ring .125

may be omitted.` vThe piston 125 has a stem 127 1o',11end 14. 4 The stem127 is further provided 'with anotch which closely cd'nnesa slideveli/e131 so thatV the slidevalve nieves relativlyfto the shifting seat123 when the stem127 reverses' its motion. The Shifting seat 123 isusejd '00 its Seat' by ,bow-spring 13 2, and theslide lvalve 131 isseated; upon the. shifting seat by a leafv spring 133 (see Figs Sto 11inciusive). The'upw'ardmotioniof the piston 125 is limited bysw'p pins134, @neef whichappears in Figs. '3, 9 to V11,"andligso that v the Vpis' t01'1"can not sealagainst the end ofthe, bushing 122. jfl'hujs theentire area of thepiston 125 is subject' on its upper sidetothe,pressurel Within'tlle bushing 122 whicljl' 'is substantially thesame as thepressurewithin the chamber 119 'bei cause ofjthe presence ofthe'passage 135. This passage is formed partly in the insert 78 andpart-1 lyin the bushing'122, as clearly Vshownin Figs@ :91:011.' Y v Theentirearea of 'the piston 125 is'subject onf its lower fece` to brakecylinder pressure com-? 4 municated-by Way. of the'annular passage 118andv Y passage 135. There are two ports in tlievalve seat. Y

formed on bushing'122, anatmospheric exhaustf port 137'and a port 133which leads to a portion` of thev delay mechanismhereinafter described.YShifting seat 123 has" two ports,139 and 141,

which extend through the shifting' seat' and which are formed onthesurface which conta'cl', s'

the valve seat on bushingf122 Withfelongations. Il'leseA elongationsinsure that in all positionsl of the shizftiruT seat 123`the port 139willbe in Vcoinmunieemen with the peri 137 end the' peru 141 will oe incommunication withtheport 133.

In Vthe uppermost"positionV of the parts, as

shown in Fig. 3, portMl is uncovered loy the slide; valve 13 1 thatpressure from the space i119 is admitted by. way- Ofi the ports 141'and1381120 the delay mechanism.

The slide valve which, when piston'125 moves downward,serves to connectthe perte 1 373111 133, under Wlh condition the delay .mechanism isvented to ate-V` mcsphere The reasen'for using the shifting seat- 123is' to permit the -piston 125 to have a reason-"j ably long travel andyet shift slide Valve 131 "to change the port'connectionsbya smallinitial travel ofthe piston from either limiting. position` after areversal or" inctien. -Wherethisg isnct irn-V y C portant, lthe shiftingseat maybe mlitted, in y which case the valve 131'W'ould cooperatedirectly.

with seat 122 andthe ports 137 and 133, Better action however, hesecured by the use of a Shifting Seat in moet eases-f l f Supported inthe iewer bedy pcrtion 76 and in the space immediately below the piston125I isa spring mechanism for controlling the downward a middle :portionofrelatiuel'y large diameter'.

V31 '1s fermed with e, recess142' leng trainsf, The simple cil spvliiiisen-.

metion of pistonj125 and its connected partsf 1 A ported eup 143"sustains 'within it agdiskjor basefllfi. Screwed inta-this base"is a1oombined guid'and stopfmade in, theprinpf a' headed and umitedm, itsupward-frieden leizaitheheed` need betweenthe`f1engee1rthe-plungeepirfsanti tine' ease, .14e isf e" coiled'cempreesign spnngji Surrounding' the spring '147a'nd 'reacti-ngbetween. ehejpieten 125 andthebewind is ai Second and lessheavilystresfse'd tensioned om ess"nspr' 14a 125. sunt-.cient to shiftthe resistance te thedewnwerej 'mei-1611er the pieten', Y

farv enough .toshift the Aslide Yvalve.,@The -im-' of L"thef device.

`1n Fig. 2e", show the possible slllgstitu'tionY of a," simple CoilSpring lASaaS proposed in Seid-11.1161" @belieben-ia eine. i whichofferschar'ac'teristics intermediate le etvveeriA double spring'arraupof s ay'two Coil smallerj le two coils will ranch pine l 7de engineer'1.51. This isprvideu Wiebe dem 152 i thereof, is fa anged plungermemberflfii'conq. A

irorn'fth'e brake pipe toward the Jtriple` -valvegbut closes againstnowin" thereverse i@v -Y space to the'other Vsidegdo'f thefpartition 1631isy amination of Figs. 12 2 and 1 4, passes aroundthe;` insert 78 andcontinues "thence inthejformjoff a drilled port to the seat ofthe'tripleslide Valve. f The 'checlval've justinentioned comprises a Y ported tube1.55 anda 'flanged head memberk 156 'which tsjonthe upperjendfthereof.This seals againstk fa gasketfand serves as a' seatjforthe ballcheokvalv ,157, 'lhischeck'valve assembly and jan encircling strainer158 are both held in place by Va' threadediplug 15S).V .This check valveand 15 strainer,assemblyuformsthe subject matter of Patent"'1,847,068, Yl1/[arch 1,' 1932.

. ,'Ifhepassage 15.4 is Vthe charging and`7qui'ck: yservice passage andterminates in aport '161 in the seat 90 of triple vslide valve' 91`(seefparticujy larly Figs: 4 to 8 inclusive).

kAs clearly shown inv Figs. 3 and v12, there is a concept underlying thepresent application. One alternative construction is'shown Ain Fig. 26and will be described hereinafter.'

'Formed' in the b ody 76 are two cylindrical recesses,.which are axiallyalined` andlwhichl are Abored from opposite sides; of thexbody 76 (seeAElige. "12 and.14)j;g' They' are separatedby a par# tition'163'." Thespace to one side ofthe partition is in communication with'thejbrake'fcylinder. passage 104 by way of lpassages 1 18and 13 6.V Thein communication withthe brake cylinder pas sage`104by way of passage164 formedpartly' in ,j the insert 78 and partlyin the body 76,V

.Mountedv inthe second named 'chamber and I sealed therein by meansof agasket 1 65is a cupshaped member 166* which` has fan.' annular valveseat'.1 67.^ -With thisV seat there lc oacts apoppet Ofjvalve168y whosestem l.1691s guided riria-hub 171' formed integrally with member 166`and extendl ingthrough an opening in'partitonflGS, which openingit'tsjreasonably closelyff `The valve 168 is urged in a closingdirectionby a spring 172,

.which' seats againstthe threaded Vplug `173 r'screwedinto body'76, and4making an yair-'tight jointtherewithf The `member 166 hasa portedflange which engages the' plug 173 so thatfmein-y ber166 .isiheldsealedpagainst 'gasket 16.5. The

with passage 174 which communicateswith pas# sage 135 and thus withchamberllQ and-space above" piston 1 25. 1 v

l Mountedvin the Ysecond named of.: rthelalinefd:v recesses is acylindricalbushing175 A which has at its innerfend an annular rim 176 ofsmaller diameter. Y gasket177 by a disk 178 which seats on a gasket 179,and which has an inward tubular extension '181` forming a Aspring guide.The disk' 178 is'- held in place by a threaded plugv 182 screwed intobody 76 and making an 'airtight seal there.- with, the plug having laninterrupted flange 183 Y l which engages t'hedisk 178without obstructing"7,5,"1-t'nenow ofair t'oand from port 138. l' 'Sliding inthebusllingy175 is a cup-"Shaped DiS- Ymethods of vrcharging are known, Aand AInight be used without departure from the broad inventive0;portsinthelange permit free communicationv The bushing is held inplace against vsfupplerne'ntal reservoir 1102.

mail

ton 184 which'is urged inward ty'sping 1st.-

vvWhen this piston :is inwardv a Ygasket y186 on-` the' end of thepistonsealsagainst the 4*Inj this'waythe eiective are'ajof its innerVend, which is'subject to brake cylinder pressure, isreduced.

vThe annulariarea outside therim y176 is 'vented' by two connected ports187, 188 which 'then bridge the length of the piston 184 and establishcommunication with port 138 by way'of tubular extension v181.V y

When piston184starts'to move outward against the oppositiono1"j"spring'1857port 188is blanked and therjentire area ofthepistonbecornes effec# tive, so that the piston moves rapidly toitsouter`limit of motion, in which'position it seals'against gasket 179.

so j

YIn' the inner position or'pistoiim the-valve 168 is held open, sincefthe piston is in thrust engagement with'thestem ofthevalve. When`piston 184 l isjin J its outer-v; position, spring 172 holds valve'168closed, assistedby pressure` fluid arriving from chamber 119 via passagev174. Ihis Valve, calleda change-over valve, forms the sub' ject matterof, and is, claimed in,application Serial No. 561,289, filed September4,1931.`

The mechanism o f `the ktriple valve has' now..

been described'except for the porting of fthe slide Valve seat, 'theslidejvalve andtliefgradu'ating valve. The (diagrammatic .showingfoiFigs. 3.

to 8, inclusivewill firstbe describedaiter which the equivalentrvactiual arrangementfot'figs. 1 7

`to 2l. willbe explained. VThe slide valveseat iSmerelya-Hat surfacemachined in thelower'portion ro'ffbu'sh'ngV as usual, and Vdimer;sioned,to receiveand aline: the' 'slide'valve .91.Thegraduating'valve92,'as exe; Y uplained, moves with thepistonstein93.. There is 10st mou-pn between the'stem' es. andthesiise:

valve 9'1, sov thatV uponintial' motion in either directionthegraduating valve 92 shifts relatively. hi-ch' is pickeduplater Theport 161 has already been mentioned.' fit, is the" port throughwhichfbrake pipe air is vented 'l infquick'servi, and through which air'flows to recharge bothl reservoirs in normal release, and

tothe slide v alvefll'v tov recharge the auxiliary V'reservoir alone Yinre;vv

stricted release.l

, Referring now specii'icallyto the diagrammatic, showing oiFigs.8130,18 inclusive: f

- There are'three ports 189,` lillfand182which 4 lead to the space 119and conseque'ntlyV to' Y .choke vport 121 and brakecylinder. passagell4.

Port189 is the portthrough which the brake pipeis vented tobraket'zylinder',iy ii'ck service. Port 191 is themain' service port.-..'ough which brake cylinder" pressure exhaustedin nrmal release andrestricted v,releaseaud through vwhich auxiliary reservoir air ilowsfto'`the brake cylinder in quickserviceand fullservice positionsxV .Port

192 'is the'v emergency port, 'throughwhicbg au' Y from Vvthe auxiliaryreservoir 97and'supplemental reservoir 102 iowsto--the brake cylinderinfemer gency and over-reduction position. There are two distinctexhaust.v pcrts, 193 and 194.`A Port y thefbushingSB to pipe 196 whichnormally would y 1923 leads byjway ,of annular passageflQ around beequipped with an ordinary retainer valve (not shown). It is' the port.through which the brake cylinder is exhausted in both normal andreYstricted release'.V The yindependentexhaust' .port

194 lopens directly to atmosphere and is V.not

controlled by theretaine'r valve at any time. it functions onlyinrestricted release position when it offers arestricted Vent toatmosphere from the restricted release positions, in both Port 19'7 isthe supplemental reservoir port. It communicates with reservoir 102 byway of pipe 101, and `is the port through whichthe supplementalreservoir is charged in normal release,

partiallyvented in restrictedrelease, and through stricted extension 199registers with port 161vv throttling the charging now. Atl this time, aswill be furtherexplained, the feed flow to the supplemental reservoir,is cut off. In all other positions the port 198 lis blanked' bygraduating valve 92 and is out vof register with all" ports in theAseat.

The ports 291 and 202 together with the recess A203 the graduating valve92, oif er th equ ick service passage through which the brake pipe isvented` tothe brake cylinder in quick service position' (see Fig'` Inquickservice position they register respectively withthe'ports 161 and139. They are devoid of function in all other positions oi the valves 91and 92', being disconnected from each other or out of register withports in the seat90. l

Fig. 6 shows quick service position, andin this position the port 161 isconnected to the p ort 189 by the ports 291, 202 and the'recess 203.This permits brake pipe airto flow to thefbrake cylinder. Port 204 is asupplemental 'reservoircharg ing port and functions only innormal'release, at which time it registers with port 197 inthe seat 9G,and is in register at its upper end with port 205 in the graduatingvalve92.

Port206 is the service port. 'In quick service position and in fullservice position it is in partial and complete register, respectively,withservice port 191 in seat`90, and its upper endr is'cleared by thegraduating valve 92 which closesA it in n cre mal release and restrictedrelease positions. The size of thisA port is controlled byconsiderations whichwill vbe discussed in connection-with opera,- tion,service position. j j v The `graduating valve 92jclos'es port '206 inservice lap position, servic'e'lap being` a position like full service,except that thegraduating valve 92 is moved to the right by the "amountof lost motion permitted between the slide valve 91 andf thestem 93.Port 207 is the emergencyport and functions only in emergency positionwhen it registers withr port `192` in seat 90. In this position-'theright hand v'end of the valve 91 clears the supplemental reservoir port197 so that both auxiliaryreservoir air vand ysupplemental reservoir airnow through the portee? and port 19210 the space 119,

The .port`208 is a bridging port which functions only in restrictedrelease'position. I n thatposi-l tion it connects ports v194 and 197 topermit a' very slow release of supplementalreservoirV air to atmosphere;Y. 1 j" The recess 209 is` the exhaust port for brake cylinderair. Atone end, as shown, it connnuf nicates with a smallthrottling portj211.`The recess 209 functions only in normalreleaseand or which` 11; servesto c'onnect'ports 191" and 193.' In normal those skilled in the art.

-vided on its lower face-withajrecess' 203 `whichlgm release the recess209bridgestlieports 191 and 193, affording free communication (see Fig'.4) but in 'restricted release the recess 209 communicates with the port191 lwhile the throttling port 211 with which it communicates, registerswith the This reduces the exhaust ilow to the capacity of throttlingport2`1-1 and thus delays release.

The relative proportions ofthe various ports which secure the desiredrates; of ilow, are subjec` to .some variation and are controlled byconside erations `which will readilyv suggest themselves to There is, -Vhowever, one important relation of ports to whichspeciric ref erencemust be' made in considering. the normal' release position (Fig.14). Itwill be` 'observed'V that the ports 198 and' 204 are bothcontrolled bylthe graduating valve 92` and that the port 204 is of slightly greaterdiameterthan port E198 so that motion of the graduating valve'to theleft sufficient to close the port' 198 completely, will never thelessnot completely close the. port 204.-.This

Adetail is important in connection with the normal release action oftriplevalves at the end'of long trains, aswill be explainedhereinafter.

. In order to secure a Compact structure 'and one Y f which could bemanufactured simply,y the slide valve'seat, slide valve and graduatingvalve are ported, as indicated Vin Figs; r`16.to 21 inclusive,thcughgvarious other arrang'ernents might be` '35 used.v Y

'The seat 90 for the slidevalve', asrshown Fig. 16,119.5 'ports 161,191,193', 194cm .igvl'ore j f spending to the similarly numbered ports inFigs.' 2 to 8, but locatedfsom'ewhat.diierently. In Fig. 16 a singleport performs the function of port 189 in quick service, and thefunction of port 192 in emergency. Consequently, on Fig. 16, this port fis designatedbyftwolegends, 189 in'Q.,S. and 192 in E. it is thuspossible-to provide a singleport with a double function. l f Referring now tojFi s. 17to 20. inclusive, ther following portsare designate'dbythe same numerals used on Figs. 3 to 8,-namely, port 199 with 129 7 itsextension v19.9, ports '201, 204,206, 207, 209y and 211, The upper endof port ',202 is indicatedrQn Fig. 17. On the lower face of the valvethis port communicates with an L-shaped recess visible in Fig. 19. InFig. 19, the outer or left endjof the `port'208 is visible, and thiscommunicates through a drilled passage in the body ofV the slide valvefwith the same L -shaped recesswithwhich the port ,202"ctSmrnunicate's'.' 'A Consequently, the L shaped recess is designatedion L 179 by two legends, 208 in R. R. and 202 in Q.S.. "These legends'signify that 'this recess. functions as a part of the portf202in'quicl; service'and as a part of theicoort 208 Vin restricted releasei As clearlyishown in l`f ig's.1'l, ,lgand 19 the 135, emergency port20'77ftalies the'forrnof a notchfcut in the side of theslide valve 91.f.

The graduating valve shown in,Fi g 21 is proj corresponds to thesimilarly numbered recess shown in Figs.' 3 to 8.- .'Ihere is, however,no throughy port `correspending"to the port '2`05l3o`i Figs. 3Y to '8.'Lxamination lof"1ig. `1'7,ihowever,v

will show that the port`s 204 .and- 198 are laterally 14d Fig: 21) edgeofthe graduating valve 92,; .Conse- 15@ f Both ports lead to the space119, and 'H5 quently, thefunction of the port 205 is performed bytheedge of the graduatingvalve.

It is believed that anyone 'skilled in they art can readily trace theoperation of the slide and graduating` valvesv from Figs. 17 toY 21inclusive, in the light of the above, explanation. There is nofunctional diiiference between this,y particular embodiment andthediagrammatic showing of i'igs.v 3 to V8. Furthermore,variousequivalent arrangements might be' adopted, theparticular i onechosen for illustration in Figs. 1G to 2l having beenv developedtousimplify manufacture. In actual practice, the ports are made byvdrilling and plugging, a familiar expedient inv this art, but intracing the ports inFigs 17 to 19j, no attempt hasbeen `madelto vshowthe actual path of the drilled ports, and the plugs, as this wouldresult in undue confusion ofthe drawings.A

`Inthes-e figures the dotted lines have been differentiated to minimizethe confusionl of ports which appear to overlap' in. projection.

M odifedy structure with charging around. triple piston l 'Thefcontrolof charging ow by ports'l98 andv 199 on triple slide valve 91, and bycheck valve 157,

produces ay valve which` is very sensitive to re- Vductions ofbrake'pipe pressure.

Whilev thisis a desirable characteristic, the sensitivity of the triplevalve'is so great that undesired applica- I tions may attimes be causedby brake pipe leakage, n or by erratic yaction of the feed valve.(associated with engineers brake valve). Y

While it is believed that modernequipment,

Yespecially modern large capacity feed valves, will meettherequirements, it is possible that much of the older equipment now inuse will not.

` To meet such unfavorable conditions, various expedients may beadopted, .for example, Athat shown in Fig. 26. Here the cylinder bushing82 is formed with' a feed groove 215. With such construction port 198and -its extension 199 are omitted from-slide valve 91. l' Y In normalrelease, charging flow is through groove `215.` In restricted releaseflow is through groove 215, and thence throughslot 219 in'rim 221 onYpiston 83. The iiow isthus throttled by slot 219, the rim v221 beingthen sealed `against the endof bushing V89'.

e YOPERA'JIIODI Charging' and `releise- `--General considerationsAssuming that an application has been made 4the engineer moves the brakevalve to full releaseposition, supplying air to the brake pipe 31 undermain reservoir pressure. yAir from the main reservoir iiows .backthrough the brake pipe and entering the. space above the piston 53 ofthe emergency vent valve,chargesthe emergency vent valve as alreadydescribed.

After an emergency application this motion ensures the closingv of thevalves 62 and 63. `These valves do not open in service applications, sothat in release following service the piston 53 merely [moves down,carrying theV pins Y59 out of contact with the valve63. f

Air also' iiows through the branch vpipe 71; cock 72 rand dustseparator' 73, tothe brake pipe connection 740i the triple-valve.'Thence it flows iby way'oi passage 1.62V to the space to the left ofthe piston 83, forcing the piston to the'right. Brake pipe pressure,particularly at the forward end ofthe train; is abnormally high duringthe initial stage or" releaseand it follows that the [triple pistons.and their connected slide valves i triplev valve.

atfthe front end of the train will be shifted to restricted releaseposition (Fig. 5), Whilethose further back in theV train will be shifted-to .normal release position (Fig. l1).` In this respect the valvefunctions substantially as does theHK-type 'Ihe proper practice for'theengineer is to shift the engineers brakeY valve to running position fromrelease position as soon as the triple valves have responded throughoutthe train and have moved to one or v.the other release position. Inrunning position of the engineers brake' valve,

main reservoir air is fed to the brake pipe through a pressure reducingvalve known as the feed valve,` and this functions to limit the brakepipe pressure tothe normal value'which is materially less than mainreservoir pressure. It often happens..

however, that the engineer leaves hisvalve in full release position toolong, and the resulting tendency is to overcharge theauxiliaryvreservoirs at the forward end of the train. The vK triple Valve opposesthis tendencyto overcharge by the restricted'rechar'ge function whichoccurs in restricted release position, but overcharges do oc-.1

One ofthe cur nevertheless with K 'triple-valves. Y characteristics ofthe present valve is its; ability to dissipate such overcharging beforean undesired reapplication of the brakescan occur when the engineersbrake valve isy shifted from release to` running position. Y vThevalvestowardfthe rear vend of they train, as has been stated, moveonlyv to normal release position, which will now be discussed.

kNormaal release In normalV release position recharging occurs past thecheck valve 157, throughthe charging port 161 in the slide valve. seat,Vand thence through charging port 198 in slide valve 91 to the slidevalve chamber. This is in direct communication with. the auxiliaryreservoir through the retard stop mechanism whichis portedV for thatThistendencytowardpartial recharge would be attended with` diiliculty atthe extreme rear end-of long trains except for the special relationdescribed with reference to ports 204 and 198. At the rear end of alongtrain brake pipe pressure rises very slowly. Consequently as soon asthe.- triple valve movesl to normal releaseposition .the

feed back from the supplemental reservoir 102 to the slide valve chambertends to raise the. pres-. sure on the right or inner side of piston 83faster than brake pipepresszure is rising on the left or outerside ofthe piston 83.'V In such case. there is a tendency for the triple pistontostart outward toward application position. In this motion. 4the Ygraduatingfvalve throttles port 198 more rapidly than port204thusslowing up the feed back'from.

the supplemental 'reservoin It followslthat under these conditionsvalve-does not move far enough to reach quick service position nor isthe port 204.1L completely the' triple blanked by the graduatingl valveiConsequently, as brake pipe pressure is furtherbuilt -up and afterreservoir pressures have equalized, the slide Vvalve Will shift to openport 198 andthe reser-4 voirs will be charged in the normal manner.

. In normal release position the brake. cylinderis rapidly exhausted toatmosphere by Wayof pipe 103,-passages 104, 164,174, 135, port 191,recess 209 and port 193. It is here assumed that the retainer valve, ifused, is in its normal .open posia tion. l

Restricted release l It has been stated that triple valves in thefrontportion of the train `move to. restricted release position `(Fig. 5). Inthis position portv204 out of register With port 197 so `that thesupplemental reservoir is isolated from the auxiliary reservoir. Thecharging ow through the ports 161 and 198 is restricted because port 161now registers Withfthe restricted extension199 of port 198.Consequently, iiow to the slide valve chamber and auxiliary reservoiroccursat a restricted rate. This reduces theV drain on brake 'i pipe airso that the rising pressure Wave in the brake pipe is propagated morerapidly toward the rear of the train. At the same time release of thebrake cylinders at the front end `of the train is ydelayed because inrestricted release position they release the supplemental reservoir 102is bied to atmosphere by way of ports 197, 208 and 194.

Normal release after restricted release' Under normal conditions ofoperation the ,pres-v sure drop in thereservoir 102 during restrictedrelease is of the order of tenpoundsper square inch. As soon as pressure-in the brake pipe r1v i levels oi to the normalwvalueV set by the-icedvalve, those triple valves which had moved to restrictedrelease positionwill be shifted to nor mal release position by the retard stop spring86. When this occurs reservoir 102 will be ten' pounds `I below itsnormal pressure. If the auxiliary reser';

voir 97 has been overcharged in restricted release, it -will then beabove normal'pressure, and there will be danger of a reapplication ofthe brakes.

This dangerv is eliminated because equalization 'l i ofthe pressures inthe auxiliary reservoir and'in the supplemental reservoir will occurwhenthe valve moves to normal release position as a result of register ofthe ports 197, 204` and 205. Y

When the triple valve shifts from-restricted vto normal releaselpositions any overcharge in. the auxiliary reservoir is promptlydissipated, and any remaining air in thel brake cylinder is rapidly.

exhrfiusted,v rthe' latter Vexhaust occurring by Way of the ports 191,209, 193. Here again itis assumed that the retainer valve is in itsnormal openposition.

Operaiion of modijcarton of Fig. 26'A l Referring tothe modificationshown in Fig. 26

-airdr remembering that withV the structure of'.

Fig'. 26 the port 198l and its extension 199 are' eliminated so thatthere can be no charging. flow past the check valve157, norrnal chargingoccurs through the. groove 215 to the slide `valve charnlo'er..v Inrestricted release the rim 221 seats against the" 'brake cylinder partlybyfw'ay of .choke 121 and" 'Sure the piston ssmoves back at least-until"the end .of .bushing I89. ,Y Consequently charging flew is then byway/pi groove 215 and Vslot '219; The Y* throttling effect of vslot2l9ensures the necessary delay in charging flow. Otherwise the chargingfunction is thesame as :described in .connection with thepreferredconstruction.

' `Quickservice. position` A When 'the` engineer makesa servicereduction of -brake-pipe pressure the triple piston moi/fes'r to theleft until it is momentarily arrested by the graduating stem 105 inquick service position (Fig. 6). Infthis position the .service portr20,6 f isopenedhythe graduating valve 92 and isin partial register withthe service port 191 inthe a seat.- At the sametirneportsV 161 and 189inthe seat register with ports and in the slide valve 91, which arethencnnected bythe recess 203 ink thegraduating valve 93.Thusarestricted ilowefromV the auxiliary reservoir to the brake cylinderoccurs,- and at the same time brake pipe air ows past check valve 157and through the quickservice ports 161, 201, 203, 202,- 1891204 the4brakel cylinder.v This quick service iiow. of brake p pipe airaccelerates the propagation of brake pipe 100 pressure` reductionthroughout the .train and` f speeds up the response oflsuccessivetriple'valves towardtherear'end of thetrain. 'l a Auxiliaryreservoir and brake pipe a-ir starting to flow through ports 206 Yand'V191 reaches the tary,- ior the accelerated drop in brake pipe pressurecauses the pistonv 83 to overpovverlthe spring 109 and moveto fullservice lDO Sition ini-which` collar 107 is arrested by flange 111 onring 112.'v

Y Fullservice posiioii. In this position quickvfservic'e port 161.lis'i1l`5 blanked A(see Fig. 7') vso vthat venting lflow'fi'f'orn thebraise pipe to the brake cylinderis terminated The service Aport206'notv, fully registers with thel service port 191 inthe seat so thatjauxiliary reser-l;v

voir air flows to Vthechamber 119 andtl'ience 1216 y the twopaths.alreadyl describedA to. the .brake cylindervunvtil `the*serviceport 206 .is lapped by' the graduating valve. i

v"T e valvesheredisclos'ed can be -given two' dif,-

, ferent operative characteristics'in service, depend; 1.115 4 135, 174,past valve 169, through passage 164 and passage 1104,to brake cylinderpi'pe'iSQy There will of. course be a minor flow through the'ehoke port121.. l. y f. y In both quick .service and` full service positionv v thesupplementalreservoir portV 197 is blankd by'. the slide valve 191 .sothatv r1`o"air flows'1 from the suppijementa reservoir to' the Vtrairecyiider., When aiixiliaryV reservoir. pressure has drcpp' dY slightlybelow equalization with brake pipe' pr graduating. valve 92 bianks the'service per# 206.1 In long trains there is atendency, after als'er"v`1ereduction of bralie' pipe v pressurey has been ir'n'ade, for'surges or Waves of pressure in tire-.brake piper to run' back' andrforthg along fthe' train.A These surges naturally' aiec't'- thetriplervvalve; and' if ift passes through quick service' position quickservice,-

14ol i its venting has the effect of accentuating or perpetuating thepressure waves in thevbrake pipe. This phenomenon isV well known inconnection with the K triple valve and has greatly vlimited the4practicable capacity of the quick service port. `If the port were madelarge enough-to give effective quick service venting the valve would'become very unstable because of the wave action in the brake pipeunder'cer'tain conditions. Hence the design has vbeen standardized ona'size of quick service,v

port vsmaller than is desired.y -j' 1t is possible to minimize thisdiiiiculty with the 1 valve here described by making the service port168 and through portV 164 to the brake cylinder.

piston 184 moves to its extreme outer position,A

' When brake cylinder pressurebuilds up to a value determined by thestrength of spring 185, say approximately iifteen pounds per squareinch, it will overpower the spring 185 and start the piston 184 outward.The initial movement exposes the entire area "ofV the piston tobrakecylinder pressure, and at lthe same time blanks the port 188 so that theallowing the `valve168 to close. The closing of the v Valve 168restricts the ow to brake cylinderto the capacity of Vchoke port121 sothat'the brake cylinder pressure acting beneath the Vpiston 125 is lessthan the pressure acting in chamber 119. Thus Ythe piston 125 tends tomove to its lowermostpo s ition and seat on the gasket 115. a `If thetriple valve should move to quick service position whilev the conditionsjust described continue, 'there would be very slight venting Vthroughthe quick service ports, because the Ypressure in A theV fchamber.119would be substantially above brake Ycylinder pressure, and so near tobrake pipe pressure that relatively little venting flow from thebrakepipe would occur. In this way the Vquick service venting, aftertheriirst venting, is smoth- Y Q ered. "As nearly as can beascertainedthe effec- "tiveness of vthequick service *ventislthenreduced to about one-quarter ofV its'normal value; and

henceja'larger quick service'vent port'canbe used without danger ofstimulating surging ory pressure waves ini. the brake'pipe. I s v Actualtests showdecidedly' beneiicial results and the practicability of usinga quick service vent of much greater capacity lthan would other-Vv wisevbe possible.V i i As brake cylinder pressure and the pressure in Lchamber 119 approachv equalization, a point will b e reached when thesprings 147 and 148 will start the piston 125 upward. The initial upwardmovement'shifts the `slide valve 131 relativelyto the shiftingfseat 123and such shifting will terminate the venting of the spaceto the right ofthev piston 184, and will admit pressure fluid from the space 119I tothespaceonthe outersideof the piston 184,- forcing piston 184 inwardandreopening the vThe pistons 125 through the entire `cycle abovedescribed,`depend ing on the intensity and duration of the serviceapplication, but while'the flowto the brake cylinder is in the secondstagegi. e., the restricted stagel thefslide valve 91 and graduatingvalve 92fasythat there is open communication to'V the Vbrake yin thespace 119 is* approximately fortyrive Ypounds per square inch. This,acting'on the pislandf184 may or may not goy iiow is reduced as aboveVdescribed.

v Emergency position d f Rapid reduction fof brake `piper pressure,whether initiated at Ythe engineers brake lvalve, or elsewhere, willcause the emergency vent valves to respond and vent vthebrakepipelocally on each car, thus greatly accelerating the propagation of`brake. pipe reduction throughout' the length of the train. Y L- If brakepipe pressure is reduced at such a rate that the pressure in chambery43v (see Fig. I2) can not be reduced through port at a similar rate,piston 53 will begforced upward to unseatl theemergency valves 63Vand62.` This will Voccurl through the chokej121,=the quick` service ventingwhether the emergency reduction has or hasnot' been preceded by'aservice reduction of' brake pipe pressure. z The effect of venting thebrake )pipe as above described, is to cause piston 83 to move-*to theleft,r overpowering the springs 109 'and `113, and coming torrest withVits margin in'sealingengagementon the gasket 81."'1t should also be fmentioned at this point that the piston 83 will assume the above namedposition whenever brake f pipepressure is approximately twelve poundsVor more below full-equalization with auxiliaryv reservoir pressure. Y iWith the piston' 83`in the positiondescribed, 105

sume the positions shown in Fig. 8, in which the supplementalreservoirport 197 is cleared bythe slide valve 91, and emergency port207-'registers with the emergency port192 inthe seat 90. vWith the partsin this position, air from the auxiliary reservoir 97 and air from thesupplemental res-- ervoir 102 flows through'the ports 287 and'192* tothe chamber 119. Notwithstanding the fact cylinder, a substantialpressure' is immediately developed in the space 119. Withreservoirsofthe size at present in use, the pressure developedl ton125, overpowersthe spring 148andmoves ther lpiston downward until-*it engages `themember 146. It will be observed that the initial motion of the'piston125 downward is-against the resistance of spring 148 alone. Therecess142 in the Aslide valve` 131now connects the ports 139,' 141, and thusvents the space at the outer side of piston 184 to atmosphere, and thevalve 13.1 interrupts thecommunication which previ'- ously existed fromchamber 119 tothe spaceto Athe outer side of piston 184.

Air then passes from the chamber 119 through the passage 135, passage174, past'valve 168, through passages 164 and '.104 to the brakecylinder pipe 103. At the same time the chokev port 121 vdelivers air ata restricted vrate from. the chamber 119 directly to'the passage 104.

The rising brake cylinder pressure is admitted through the annular spaceV118 and the passagey 136 to thefspace at the inner .end ofthe'piston149 184. The springs 185 and 172 are so jchosenr that when brakecylinder pressure reaches a definite value, say fifteen pounds perfsquare inch gage, the piston'184 will start togmove outward.

The initial movement in, this direction blanks 145 the port 188 whichpreviously .vented the space outside the rim. 176, and at the same timeexposes the entire area of piston 184 to brake cylinder pressure.V'.TJhepiston on its outer side is,`

open' Vto Aatmospheric'pressure at this time. Con-- inseam;

pounds per square inch. The rising pressure is suicient to move'thepiston 125y to its lower limit of motion against the resistance of the.1 5 springs 147 and 148. In such lowest position it seals against thegasket 115. The piston is provided with a projecting bead which ensuresa tight seal and reduces the effec'- f` tive areaof the lower side. Thisfurther down- 29, ward motion does not change the relation of the slidevalve 131 to the shifting seat 123, nor

is there any'change of relation between the ports 13 9 and 141 in theshifting seat andthe corre# spending ports 137 and 138 in the bushing122. 2 5,v The additional motion does, however, Vdevelop a greaterreactive force in the springs 147 and 148',

ensuring the prompt upward motion of the valvel 131 at the propertin-le.

The movement' of the piston 184 outwardv ini-l' 30,-; tiates the secondstage of `emergency application.-

'The duration ofthe second stage is dependent primarily on the size ofthe choke port121. This may desirably be so chosen that ybrake cylinderpressure will rise from the value attained in the value, say thirty-livepounds, in achosen period of say eight seconds. With the Values justassumed, the combined vstrength of the springs 147 and 148l should besuch that when brake cylinder pres- Qfsure has risente thirty-fivepounds, the piston '125 will start upward under'the combinedurge ofthetwo springs, and brake cylinder pressure, which reaches the lowerside of the piston through the passages 118 and 136; f 4e; The efect`ofv the initial upward motion i's'to 'move the slide valve 131 so thatports 139 and 1:41 are disconnected (see Fig.- 11) and immol diat'elythereafter the space-119 is connectedy by way of ports 141 and 138 withthe space at the? fouter side of the piston 184. As soon as thisocvcu-rs'a preponderating pressure develops on the outer side of piston184 and this pressure together with the'spring 185,'will immediatelyforce the piston 184 inward to its limit of motion,

Iunseating the valve 168 and initiating the third stage. The unseatingof valve 168 allowsvrapid ow to bel resumed from the chamber 119 throughpassages' 135 and 174 past valve l'and through passages 164 and 104 tothe brake cylinder pipe 103.V Rapid equalization of pressures inv bothrreservoirs and brake cylinders now occurs so that brake Acylinderpressure reaches its maximum value almost immediately.

TheA purpseiof this sequence of operationsv jis toasecure a denite cycleof braking pressures in emergency applications. In the first phase thereis a rapid rise of pressure to a point sufficient to ensure that `allthe brake shoes areforced against the wheels.` Experience indicates that7f0' ja pressure of'approximately iteen'pounds per' initial movement ofthe valve 131, aftera reversalV 35, rst stage, say fteen pounds, toanother chosenv not move,y but the valve131r does move, relatively tothe. seat 123, far' enough to produce thev neces-v` because 'the ventingfunction of' v these valves is triple valve 8,3*will move'v to emergencyposition` so that oneach car supplemerital reservoirair,

slowrise gives an.- opportunity forthe slack to run in and for thetrainY thus",tojbecomebunched, Experience indicates that .alperiodofa'ruproxie'` mately eight seconds is desirablefor the'second stage, butthis period is subject to variation. The duration of lthe, second 'stageis vcontrolled pri-' marilyby the sizeof choke y12,1 and secondarilybythe lcombined strengthjiof springs 147 and' 148. The combined strengthorthese two springs defi termines the, brake cylinder pressure'atwhichthe second stage ends. At the end oi the secondstage"thefslaclrwill`bebunched and the brakesjwillf. beveffective ,to produce pronounceddeceleration of the train., 'Th'e third stageis marked by rapid rise ofbrake. cylinderV 'pressure to the A'nlaximum attainable; This maximumisdependent on the size of the two reservoirs with reference tothe sizeoff-the v brake' cylinder 'andthe'length of rpiston travel. j The eiect'of the vshifting seat 123 willnow lhe more "readily -understoodf Itpermits Aa "relatively long travel rof the piston 125V and ensures thatlthl of direction, will'produce the desired shift in re-A lation betweenthe'valvef131 andthe shiftingv seat 12,3. f The purpose in using thedualfsprings 147 and 148 is toensure relatively low4 initialresistance lagainst the downward -movement of vthe piston' 125. The spring 148acting alone offers relatively light resistance.4 yConsequentlyI theYpiston -125 starts downward under a moderate pressure and is brought torestwhen Iit engages themember 146. i' 's this' is'spring sustain ed, Aarrest of the piston is effected without Vundue sh'ockfvv '1" The lostmotion' betweenfthe pistonjstem ,and the shifting seat 123' is'{sucl 1that in this .initial downward motion of the piston'th'e seat 123 doessary change relationshipof Athe ports.

^ After the Jcommence'ment of thesecondstage the piston' overpowers both springs 147 and 148 At the'endoi the second Istageitis thus subjectto relatively heavy upward spring .pressurejwhic'h willensure its.prompt movement in an upward` direction at the proper time.'

Y The piston is "shownmoving upward 'in Fig.r 11 with valve 131 in acriticalposition.relatively 12.5, to shifting seat 123, thatlathe-positionin which the port relations Vchange,v

,v:Ernergcncyfapplictioh following a seczce L -..app lisationw` "j 13gI'f an emergencyfapplication'follows a-service applicationr theemergency vent valves through-" out the trainwill open and vent thebrake pipe;

dependent on the rate" of brake pipe pressure', reduction, noten', therelationof'brake pipe` presel sure to' auxiliary reservoir pressure, aswasthe,l

rcase in the standard K triple. Consequentlyj,.the`

emergency pressure drop will be'rapijdly' propagated throughout the uentirel'engthf of the' 'tra'.in"'1491y no matter how heavy a serviceapplication may havebeenmade previously.` 'It follows that eachV aswellvas aui'iliaryr reservoir air, is fed tofthe chamber 119. i x l j ItVthe4v port 206 is so 'dimensioned` that the; piston125 does net'move'downwardinfservice applications, and if the service applicationprels.

ceding the ,emergency application l was `a "light" f sof y Y one, thepistons Y125Y and 184 will act` through their regular cycle, as 'abovedescribed, in emer" geney operation, though the third stage will bereached more :rapidly kthan normally because it will takeV ashorter timeVfor the brakecylinder pressuret'oreach fthe value at which the piston125 will rise. If said lprecedingservice applicationmhas produced asubstantial brake cylinder '.3,0 tinued and `somewhat accelerated.:

pressurethis pressure,V acting beneath the piston 125, will prevent itfrom moving downward.` Insuch case, the pressures in" the two reservoirsand in the brake cylinder will rapidly equalize. This is an entirelysatisfactory sequence of operation, ,because fthe preceding 'serviceapplication would have conditioned fthe train for theemergencyapplication.' y Y s arrangement of the valve vReferring now to that inwhich the port 206 is solargethat the piston 125 Ais affected inserviceapplications. -f an emergency application follows a service application,the effect is merelyY to supply additional vhigher pressure' tothechamber 119 so that vthe pistons 125 and 184 will aotthrough theirnormal f2: 5 three-stage cycle, but this cycle vwill .be expeditedsomewhat by the more rapid flow through the choke 121.` It makes nogreat difference Vat what point in the three-stage cycle the emergencyapplicationcomes, thecyclewl becon- General, structural considerationsThe arrangement `shown'in Figs.'12 to 22 has ,been foundto be compact,economical to manufacture, andoiers decided accessibilityto theoperating parts]y It also permits use'to be made ofmany'components.salvaged from the K triple. [Whileit is preferred to useapacking ring 126 on the vpiston 125, 'this can be omitted. The

` piston'iis urgedv downward initially by rather sharp pressurerise andwhen it Vreaches its lowermost position issealed by the gasket'l15. Theomission ofthe piston ring would allow the .pis-

' ton to movey more freely, which is a desirable characteristic. Itsomission is entirely permissible and'further experience with thevalve'may indicate that vit is desirable, particularly in-valves soarranged that 'the piston 125 does not move downward in serviceapplications. Y 1 g The spaces at opposite'sides of thepartition 16,3are .both at brakeA cylinder pressure, andY there is no occasion for aparticularly close t of partition 163.

between the stem 169 andits guidefin the bushing v171 or betweenthebushing 171 andthe walls rstv rush of air from acting on V,the lowerside of the piston 125 and thus 'rendering its immediatedescent'uncertain.; and also tol prevent the `first rush of air fromcausing premature motion of piston184. These results can be secured,`

Vdespite slight leakage past or vthrough the partition 163.

. The piston 184 seats onlgaskt in both its jlimiting positions. Initstravel 'outward it moves rapidlyfunder a-markedpressure differential. Inits inward motion, which occurs atvthe` com- -iniencementof the thirdstage, the only .leakage would lberfrom the chamber 119 to the brake'jcylinderf port, which is Aimmaterial at the comm'encement of vthethird stage. Accordingly, it isunnecessary thatfthe piston 184 make Vaparticularlytight t'in the bushing 175. A free ,t

is desirable` `to ensure prompt motion of the. piston 184.'V Iv 4 ,e i,The above facts'permit quite simple and in- Inv emergency applications fthe n functions of, the'partition 163 are to'prevent the l expensiveconstruction of the Working partsjfa'nd offer substantial advantagesfrom the` mainte-V nancey and manufacturing standpoints. y

While `I have shownY av particular form of emergency vent valve,l otherapproximately equivalent formsareknown andv might be substituted. Iprefer tov locate this ventA valve on the brake vsoYV pipebecausethisappears to be the best posi- .l ing. Y

The retard stop spring 8 in the present 'device is stronger than `retardstop springs used in the conventional K type triple. lIn theK typetriple the auxiliary reservoir was charged through a groove lin thecylinder bushing, and in restricted recharge position a groove such vasthe groove 219 in the rim 221 (Fig.1 26) Vcontrolled the charging rate.As the charging groove in the cylinder bushing had a considerablecapavcity, a relatively sharp risev in brake pipe pressure was necessary toshift the; triplev pistontov restricted recharge position. To' ensurelmotion tol restricted recharge position, a rather weak Aretard stopspring was used. Furthermore, after `the K triple valvefwas inrestricted recharge position, the effective area onthe innerside of the.triple piston was reduced to the area within the rim 221.- This fact,in conjunctionV with the Vvvealnkess of the retard *stopv springconduced to sluggish motion from restricted rechargeto normal rechargeposition.

.lnthe preferred form of the present device. the entire inner side ofthe piston 83 is subject to auxiliary reservoir pressure, and the retardstop spring isheavier. Consequently the prompt l and certa'inret'urn tonormal position is ensured.

By usingQacharging vport 161 of relativelyVv small capacity, togetherwith a heavy retard stop spring, it is possible yto secure crisp motion'between the two: release and 'recharge positions,y and to keep thecharging drain on the brake pipe to a minimum. Ilfhe fact that thesupplemental reservoir is partially vented in-restrictedrechargeposition, diminishes thek tendency toward reap-` plication afterrestricted recharge, and. in some kdegree permits theluse of astronger'retard stop spring. ,It is therefore possible to co-ordinatethe size of the. charging port, the vrate of venting` of kthesupplemental v reservoir in restricted release, andthe strength of theretard stopspring, to` meet the severe requirements of service. By so fcoordinatingv the vari-ous features above outlined,V itV is; possible tosecure a more rapid releasing wave inthe brake pipe.` lAlsoitispermissible to leave the engineers brake valve in full release positionlonger than is` practicablegwith K type valve, and when the engineersbrake valve'is shifted to running-position, there is agl'norel pre,-

'oise return of the triple valve from restricted rei charge to normalrecharge position. v n Y :The broadl idea of ventingy the supplemental.

lReservoir in restricted release position and then allowingysupplemental reservoir pressure to equalize withl the auxiliaryAreservoirpressure in,

normal release position,ris described and claimed in the patent'toCampbell, No; A1,632,756,dated June 111i, 1927., v'Ihat patentdoesnot,however, disclose this feature in combination' with thel

